The present invention relates to a programmable remote control transmitter and, more particularly, to a programmable remote control transmitter for emulating any one of transmitters for remote-controlling electrical devices.
Various types of electronic products have been used at home to provide convenience in daily life in recent years. Most electric products have so-called remote controllers as transmitters for electrically remote-controlling the electric devices. Since every electric device employs a transmission system of a unique type, a transmitter for a given electric device cannot be used for another electric device. If the number of electric devices is increased, the number of types of transmitters is accordingly increased. When a large number of remote controllable electric devices are installed in a house, the user is often confused of selecting a transmitter appropriate for each electric device.
In order to solve this problem, the present applicant has proposed a programmable remote control transmitter. This programmable remote control transmitter receives various remote control codes from all transmitters used in the house and decodes these codes. The decoded remote control codes are stored in a memory. Where the remote control transmitter is used, a type of the electric device to be available is selected and the selected electric device is remotely controlled in accordance with the data stored in the memory which correspond to the remote control codes of the selected electric device. In the learning process, the programmable remote control transmitter receives signals from another transmitter for, e.g., a television receiver, and decodes the signals to obtain data. The data are then stored in a nonvolatile memory. When data are stored in the nonvolatile memory, data compression is performed to reduce a required memory capacity. In order to compress data, pulse burst and pulse off components which constitute data sent from the transmitter for the television receiver are classified into bins to learn the data. Data compression is then performed according to bin data obtained by learning. Each bin comprises 2-byte data. If a bin is "A", it represents the pulse burst component. If a bin is "B", it represents the pulse off component. The pulse burst and pulse off components are classified according to one or more bins. Various combinations of bins are proposed according to various transmission systems, and the number of bins is changed for each different system. A threshold value is predetermined to discriminate the pulse burst and pulse off components so as to classify pulse burst and pulse off components falling within the nominal range into a given or another bin. One such conventional programmable remote control transmitter is described in detail in Japanese Patent Prepublication No. 60-254898, corresponding to U.S. Pat. No. 4,623,887 (Welles II) issued Nov. 18, 1986.
In this transmitter, since data is compressed on the basis of repetition of unit data to be discriminated, data compression is limited by the length of unit data. Compactness required as a remote control transmitter and remote control performance are limited. If the number of control signals to be operated by the remote control transmitter is increased, a memory capacity and hence the number of peripheral circuits are increased. As a result, the total power consumption of the transmitter is increased, thus requiring a large-capacity battery or frequent replacement of batteries. In order to improve control performance of the remote control transmitter, the transmitter housing becomes bulky or the battery must be frequently replaced with a new one, resulting in cumbersome operation.